Are you wanting to extend you Microsoft 365 Personal or Family license
Go to https://setup.office.com/?ms.officeurl=setup&ref=accountportal
- Sign in with the Microsoft account you want to extend with the new license key
- Once signed in, enter your product key – in the format XXXXX-XXXXX-XXXXX-XXXXX-XXXXX
- Choose your Region and click Next
- Follow the rest of the prompts
- Your license should be added to your account and extend your license period
Then click Redeem a code or prepaid card and follow the prompts